1. Field of the Invention
The present invention relates to a wide-angle lens suitable for a single-lens reflex camera and a digital camera, an optical apparatus using thereof, and a method for focusing the wide-angle lens.
2. Related Background Art
There has been proposed a retrofocus lens with a leading lens having negative refractive power as a wide-angle lens capable of securing a sufficient back focal length suitable for a single-lens reflex camera and a digital camera in spite of a short focal length. In this lens type, there has been proposed a one constructed to be a large aperture having an f-number of about 1.4 such as Japanese Patent Application Laid-Open No. 11-030743.
However, in the conventional wide-angle lens, various aberrations have not been sufficiently corrected.